1. Technical Field
The present invention relates to a projector.
2. Related Art
Projectors using a discharge lamp such as a high-pressure mercury lamp or a metal halide lamp are put into practical use. As such a projector, there is disclosed a projector having a device for varying the intensity of the light source in sync with a video signal in accordance with a color separation section or the like in, for example, JP-A-2003-102030. However, JP-A-2009-237302 describes the problem that the consumption of the electrode of the discharge lamp becomes marked if the intensity of the light source is varied simply. Further, in recent years, projectors using a discharge lamp such as a high-pressure mercury lamp or a metal halide lamp to output a stereoscopic image are put into practical use. As one of the methods of outputting a stereoscopic image, there can be cited a method of switching between a right-eye image and a left-eye image to output them alternately (an active shutter glasses method such as “XpanD beyond cinema (a trademark of X6D Limited)”). In this method, a pair of active shutter glasses synchronized with the video signal is used for showing the right-eye image to the right eye and the left-eye image to the left eye to thereby make the image stereoscopic using the parallax between the right and left eyes.
In the case of projecting the stereoscopic image using the method of alternately outputting the right-eye image and the left-eye image, the amount of the light input to each of the right and left eyes becomes a half as much as in the case of projecting a conventional planar image (a two-dimensional image). Further, since the image does not seem stereoscopic if the cross talk in which the right-eye image enters the left eye and the left-eye image enters the right eye occurs, it becomes necessary to provide the period in which the both active shutters are closed. Therefore, there arises a problem that in the case of projecting the stereoscopic image using the method of alternately outputting the right-eye image and the left-eye image, the image seems darker than in the case of projecting the conventional planar image. Although it is also possible to simply raise the drive power in order for making the image seem brighter, there arises a problem that the power consumption of the projector is increased, and the deterioration of the peripheral components is promoted due to the raise in the drive power.